Impact of tumour necrosis factor‐α polymorphisms on irritant contact dermatitis

BACKGROUND: Genetic variations in genes coding for cytokines involved in skin inflammation may alter their expression, thus changing the susceptibility to irritant contact dermatitis (ICD). OBJECTIVES: To determine the prevalence of polymorphisms in the cytokine genes TNFA-238 and TNFA-308 in patients with occupational ICD, and to compare it with that in controls. METHODS: In a case-control study, 478 patients with occupational ICD of the hands were genotyped for TNFA-238 and TNFA-308 polymorphisms. The results were compared with those for 393 apprentices from the same high-risk occupations (controls). RESULTS: For a carrier of a variant TNFA-238A allele, the odds ratio (OR) of acquiring ICD was 0.57 [95% confidence interval (CI) 0.34-0.97], suggesting a protective effect of the A allele. The genotype distributions were 94.4% wild type (G/G), 5.6% heterozygous (G/A) and 0% homozygous for variant allele (A/A) in patients, and 90.9%, 8.5%, and 0.6%, respectively in controls. In contrast, carriers of the variant TNFA-308A allele had an increased risk of ICD [OR 1.33; 95% CI 1.05-1.74; G/G 66.4%, G/A 31.2%, and A/A 2.4% (patients) versus 73.5%, 24.6%, 1.9% in controls]. CONCLUSIONS: Individuals with a TNFA-238 polymorphism are less prone and those with a TNFA-308 polymorphism are more prone to develop ICD of the hands, suggesting a protective versus a detrimental effect of the A allele respectively.